How do read data dictionary config from EmaConfig.xml using EMA Java API ?

Mani.A
Mani.A
in EMA

Hi All,

I have data dictionary xml in my EmaConfig.xml as below.

In the EmaConfig.xml
<Dictionary>
   <Name value="Dictionary_2"/>
   <DictionaryType value="DictionaryType::FileDictionary"/>
   <RdmFieldDictionaryFileName value="./etc/RDMFieldDictionary"/>
    <EnumTypeDefFileName value="./etc/enumtype.def"/>
</Dictionary>

I'm having trouble finding a sample on how to read the above config using EMA Java API.

I have the below to read consumer config from EmaConfig.xml

OmmConsumerConfig config = EmaFactory.createOmmConsumerConfig().consumerName("Consumer_1").username("userid");

I'm looking something similar above to read the data dictionary config.

Please provide some pointers.

Thanks in advance.

Mani

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Best Answer

  • Gurpreet
    Gurpreet
    Answer ✓

    Hi @Mani.A ,

    The data dictionary part of config is used in creating the consumer and is used by EMA automatically. In the consumer block, just include a reference to the dictionary block that you plan to use like this:

    <Consumer>
      <Name value="Consumer_1"/>
      <Channel value="Channel_1"/>
      <Logger value="Logger_2"/>
      <Dictionary value="Dictionary_2"/>
    </Consumer>

    See the EMAconfig.xml examples here.

Answers

  • Mani.A
    Mani.A

    Thanks @Gurpreet

    In my java code, how I can get access to data dictionary "Dictionary_2" configured for the Consumer_1 in the EmaConfig.xml ?

    Currently I'm doing the below:

    DataDictionary dataDictionary = EmaFactory.createDataDictionary();
      dataDictionary.loadFieldDictionary("RDMFieldDictionary");
      dataDictionary.loadEnumTypeDictionary("enumtype.def");



  • Gurpreet
    Gurpreet

    @Mani.A ,

    I am trying to understand why you need to do this? Once the dictionary is defined in the config file, it is automatically loaded either from the ADS or from local disk, and is available for use in the EMA application.You don't need an explicit access to data dictionary object.

  • Mani.A
    Mani.A

    @Gurpreet Initially, I had field ids hard coded as below. Our clients use field names not field ids.

    OmmArray fieldAarray = EmaFactory.createOmmArray();
       fieldAarray.fixedWidth(2);
       fieldAarray.add(EmaFactory.createOmmArrayEntry().intValue(22)); //BID
       fieldAarray.add(EmaFactory.createOmmArrayEntry().intValue(25)); // ASK


    Later I used the data dictionary api to get the IDs for the field names as below:

    DataDictionary dataDictionary = EmaFactory.createDataDictionary();
            dataDictionary.loadFieldDictionary("RDMFieldDictionary");
            dataDictionary.loadEnumTypeDictionary("enumtype.def");
            System.out.println(dataDictionary.entry("BID").fid());


    Is there a way to get the field ids for a field name ? Or any best practice for the above ?

    Thanks in advance.

    Mani

  • Gurpreet
    Gurpreet

    Unfortunately not. The EMA loaded data dictionary is only available in the context of the callback method. You can either continue to use filename to load your DD, or see the example ex332_Dictionary_Streaming for how to subscribe to dictionary from the network.

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